Ch 17 Robbins Flashcards
A 30-year-old woman sees her physician because she has had diarrhea and fatigue and has noticed a 3-kg weight loss over the past 6 months. On physical examination, she is afebrile and has mild muscle wasting, but her motor strength is normal. Laboratory studies show no occult blood, ova, or parasites in the stool. A biopsy specimen from the upper jejunum is obtained, and microscopic findings are reviewed. The patient is placed on a special diet with no wheat or rye grain products. The change in diet produces dramatic improvement. Which of the following microscopic features is most likely to be seen in the biopsy specimen?
□ (A) Lymphatic obstruction □ (B) Noncaseating granulomas □ (C) Villous blunting and flattening □ (D) Foamy macrophages within the lamina propria □ (E) Crypt abscesses
(C) This patient has malabsorption that responded to dietary treatment. She probably has celiac disease (gluten sensitivity). The histologic features of celiac disease are flattening of the mucosa, diffuse and severe atrophy of the villi, and chronic inflammation of the lamina propria. There is an increase in intraepithelial lymphocytes. Lymphatic obstruction occurs in Whipple disease. In addition, foamy macrophages accumulate in the lamina propria. They contain PAS-positive granules, which, under electron microscope, show an actinomycete calledTropheryma whippelii. Noncaseating granulomas are found in the intestinal wall in Crohn’s disease. Crypt abscesses are nonspecific and can be seen in inflammatory bowel disease.
Two days after eating a chicken salad sandwich, a 35-year-old man experiences cramping abdominal pain with fever and watery diarrhea. Physical examination shows mild diffuse abdominal pain on palpation, but there are no masses. Bowel sounds are present. A stool sample is negative for occult blood. He recovers completely within a few days without treatment. Which of the following infectious organisms is most likely to produce these findings?
□ (A) Yersinia enterocolitica □ (B) Escherichia coli □ (C) Entamoeba histolytica □ (D) Salmonella enteritidis □ (E) Rotavirus □ (F) Staphylococcus aureus □ (G) Bacillus cereus
(D) Infection by one of several Salmonella species (not S. typhi) causes a self-limited diarrhea. This is a form of food poisoning, typically from contaminated poultry products. Yersinia enterocolitica is most often found in contaminated milk or pork products and may disseminate to produce lymphadenitis and further extraintestinal infection. Various diseases result from contamination with different strains of Escherichia coli, based on the characteristics of the organisms, and whether they invade or produce an enterotoxin. Poultry products are usually not contaminated with E. coli. Amebiasis from Entamoeba histolytica can be an invasive, exudative infection. The stools contain blood and mucus. Rotavirus is most often seen in children; in adults, a self-limited watery diarrhea occurs. There is no particular association between rotavirus infection and a specific food product. Staphylococcus aureus causes an acute onset of abdominal pain, bloating, and diarrhea not by directly infecting the gastrointestinal tract, but by producing an exotoxin while growing on food that is subsequently ingested. Bacillus cereus growing in foods such as reheated fried rice produces an exotoxin, which, on ingestion, can produce acute onset of nausea, vomiting, and abdominal pain.
A 38-year-old woman has had nausea for the past 6 months. She reports no vomiting or diarrhea. On physical examination, there are no remarkable findings. Upper gastrointestinal endoscopy shows diffuse gastric mucosal erythema with focal mucosal erosions, but no ulcerations. The esophageal and duodenal mucosal surfaces appear normal. Microscopic examination of gastric biopsy specimens shows increased numbers of neutrophils, lymphocytes, and plasma cells in the mucosa; edema; focal mucosal hemorrhage; and loss of the surface epithelium. No Helicobacter pylori organisms are seen. Laboratory studies show a normal serum gastrin level. Which of the following pharmacologic agents is most likely to produce these findings?
□ (A) Acetylsalicylic acid (aspirin) □ (B) Acyclovir □ (C) Chlorpromazine □ (D) Cimetidine □ (E) Clindamycin □ (F) Omeprazole □ (G) Prednisone
(A) These findings are consistent with an acute gastritis. Heavy consumption of ethanol is probably the most common cause, but aspirin and nonsteroidal anti-inflammatory drugs, smoking, and chemotherapy agents can produce the same findings. Acyclovir (used to treat herpes simplex virus infections), chlorpromazine (used to treat nausea), and prednisone (a steroidal anti-inflammatory drug) do not have the same association. Cimetidine and omeprazole are used to treat peptic ulcer disease by reducing gastric acid production, increasing the serum gastrin. Cimetidine is an H2 receptor blocker, and omeprazole is a proton pump inhibitor. Clindamycin is a broad-spectrum antibiotic that may alter flora in the lower gastrointestinal tract.
One year after having an acute myocardial infarction, a 55-year-old man saw his physician because of severe abdominal pain and bloody diarrhea. On physical examination, the abdomen was diffusely tender, and bowel sounds were absent. Abdominal plain films showed no free air. Laboratory studies showed a normal CBC and normal levels of serum amylase, lipase, and bilirubin. His condition deteriorated, and he developed irreversible shock. At autopsy, which of the following lesions is most likely to be found?
□ (A) Acute appendicitis □ (B) Acute pancreatitis □ (C) Intestinal infarction □ (D) Acute cholecystitis □ (E) Pseudomembranous colitis
(C) The patient’s history of myocardial infarction suggests that he had severe coronary atherosclerosis. Atheromatous disease most likely involved the mesenteric vessels as well, giving rise to thrombosis of the blood vessels that perfuse the bowel. The symptoms and signs suggest infarction of the gut. Acute appendicitis rarely leads to such a catastrophic illness, unless there is perforation. (The absence of free air in the radiograph argues against perforation of any viscus.) Acute pancreatitis can be a serious abdominal emergency, but the normal levels of amylase and lipase tend to exclude it. Acute cholecystitis can produce severe abdominal pain, but bloody diarrhea and absence of bowel sounds (paralytic ileus) are unlikely. Pseudomembranous colitis develops in patients receiving antibiotic therapy.
A 59-year-old man has had nausea and vomiting for several months. He has experienced no hematemesis. On physical examination, there is no abdominal tenderness, and bowel sounds are present. Upper gastrointestinal endoscopy shows erythematous areas of mucosa with thickening of the rugal folds in the gastric antrum. The microscopic appearance of a gastric biopsy specimen with a Steiner silver stain is shown in the figure. Which of the following toxins from these organisms is most likely to be present on the luminal surface?
□ (A) Cysteine proteinase □ (B) Heat-stable enterotoxin □ (C) Shiga toxin □ (D) Vacuolating toxin □ (E) Verocytotoxin
(D) Helicobacter pylori organisms reside in the gastric mucus and are associated with various gastric disorders, ranging from chronic gastritis with erythema and thickened rugal folds, as in this case, to peptic ulcers and to adenocarcinoma. H. pylori organisms elaborate several toxic substances that injure the epithelium. Vacuolating cytotoxin (VacA) causes cell injury characterized by vacuolization. Another H. pylori gene from a pathogenicity island encodes cytotoxin-associated antigen (CagA) and is present in many patients with chronic gastritis and peptic ulcers and increases their risk for gastric cancer. Cysteine proteinases produced by Entamoeba histolytica aid in tissue invasion. Heat-stable enterotoxin is produced by strains of Escherichia coli that cause traveler’s diarrhea. Shiga toxin is elaborated by Shigella flexneri organisms, which cause a form of bacillary dysentery. Verocytotoxin produced by some E. coli strains is associated with hemolytic-uremic syndrome mediated by endothelial injury.
A 23-year-old primigravida gives birth at term to a boy. Ultrasound examination before delivery showed polyhydramnios. A single umbilical artery is seen at the time of birth. It is noted that the infant vomits all feedings, then develops a fever and difficulty with respirations within 2 days. A radiograph shows both lungs and the heart are of normal size, but there are pulmonary infiltrates and no stomach bubble. What is the most likely diagnosis?
□ (A) Achalasia □ (B) Diaphragmatic hernia □ (C) Esophageal atresia □ (D) Hiatal hernia □ (E) Pyloric stenosis □ (F) Squamous cell carcinoma □ (G) Zenker diverticulum
(C) An esophageal atresia is often combined with a fistula between the esophagus and trachea. Gastrointestinal obstruction in utero can lead to polyhydramnios. The presence of a single umbilical artery suggests additional anomalies are present. Vomiting in an infant risks aspiration with development of pneumonia. Achalasia is incomplete relaxation of the lower esophageal sphincter and is usually not manifested at birth. Absence of a diaphragmatic leaf, usually on the left, results in herniation of abdominal contents into the chest and functional gastrointestinal obstruction, but in this case normal-sized lungs suggest no herniated contents were present. A hiatal hernia from widened diaphragmatic muscular crura predisposes to gastroesophageal reflux, and obstruction is not a typical complication. Pyloric stenosis is a cause for gastric outlet obstruction in an infant, but the onset is usually in the second or third week of life. Squamous cell carcinomas are seen in adults. A pharyngoesophageal (Zenker) diverticulum above the upper esophageal sphincter is usually a disease of adults.
A 70-year-old man saw his physician for a routine health maintenance examination. On physical examination, there were no remarkable findings, but a stool sample was positive for occult blood. A colonoscopy was performed and showed a 5- cm sessile mass in the upper portion of the descending colon at 50 cm from the anal verge. The histologic appearance at low power of a biopsy specimen of the lesion is shown in the figure. The patient refused further work-up and treatment. Five years later, he sees his physician because of constipation, microcytic anemia, and a 5-kg weight loss over the past 6 months. On surgical exploration, there is a 7-cm mass encircling the descending colon. Which of the following neoplasms is he now most likely to have?
□ (A) Adenocarcinoma □ (B) Non-Hodgkin lymphoma □ (C) Carcinoid tumor □ (D) Leiomyosarcoma □ (E) Mucinous cystadenoma □ (F) Squamous cell carcinoma □ (G) Villous adenoma
(A) This patient had a large villous adenoma, as shown in the figure. There is a high probability that large villous adenomas will progress to invasive adenocarcinoma. When they occur in the descending colon, these lesions are annular and cause obstruction. In the colon, non-Hodgkin lymphomas are far less common than adenocarcinomas, and they do not manifest as mucosal sessile masses. Carcinoid tumors are typically small and yellowish, and most grow slowly. Leiomyosarcomas are rare; they produce large bulky masses, but they do not arise on the mucosa. Mucinous cystadenomas are cystic and are more likely to arise in an ovary or in the pancreas. Squamous cell carcinomas can arise in the esophagus or at the anorectal junction. The original lesion in this patient was a villous adenoma.
A 70-year-old man with a lengthy history of chronic alcoholism has had increasing difficulty swallowing and has noticed a 6-kg weight loss over the past 2 months. On physical examination, there are no remarkable findings. Upper gastrointestinal endoscopy shows a 3-cm ulcerative mass in the midesophagus that partially occludes the esophageal lumen. Esophagectomy is performed; the gross appearance of the lesion is shown in the figure. Which of the following is most likely to be seen on microscopic section of this mass?
□ (A) Multinucleated cells with intranuclear inclusions □ (B) Squamous cell carcinoma □ (C) Dense collagenous scar □ (D) Adenocarcinoma □ (E) Thrombosed vascular channels
(B) This large, ulcerated lesion with heaped-up margins is a malignant tumor of the esophageal mucosa. There are two main histologic types of esophageal carcinomas—squamous cell carcinoma and adenocarcinoma—with distinct risk factors. Smoking and alcoholism are the most frequent risk factors for esophageal squamous cell carcinoma in the Western world. Adenocarcinoma is most likely to arise in the lower third of the esophagus and to be associated with Barrett’s esophagus. Intranuclear inclusions suggest infection with herpes simplex virus or cytomegalovirus, both of which are more likely to produce ulceration without a mass; both occur in immunocompromised patients. Chronic inflammation may lead to stricture and not to a localized mass. Thrombosed veins occur in sclerotherapy for esophageal varices; they do not produce an ulcerated mass. A dense, collagenous scar of the mid esophagus is uncommon, but it may occur after injury from ingestion of a caustic liquid.
A 33-year-old man who lives in New York is bothered by a low-volume, mostly watery diarrhea associated with flatulence. The symptoms occur episodically, but they have been persistent for the past year. He has experienced a 5-kg weight loss. He has no fever, nausea, vomiting, or abdominal pain. On physical examination, there are no significant findings. A stool sample is negative for occult blood, ova, and parasites, and a stool culture yields no pathogens. An upper gastrointestinal endoscopy is performed. A biopsy specimen from the upper part of the small bowel shows severe diffuse blunting of villi and a chronic inflammatory infiltrate in the lamina propria. Which of the following serologic tests is most likely to be positive in this patient?
□ (A) Anticentromeric antibody □ (B) Anti–DNA topoisomerase I antibody □ (C) Antigliadin antibody □ (D) Antimitochondrial antibody □ (E) Antinuclear antibody
(C) The clinical and histologic features suggest celiac disease. Characteristic serologic findings include positive tests for anti-transglutaminase, anti-gliadin, and anti-endomysial antibodies. This chronic disease may manifest in young adulthood but may escape diagnosis. Women are affected more than men. Celiac disease results from gluten sensitivity. Exposure to the gliadin protein in wheat, oats, barley, and rye (but not rice) results in intestinal inflammation. Gliadin sensitivity causes epithelial cells to produce IL-15, which in turn leads to accumulation of activated CD8+ T cells that bear the NK cell receptor NKG2D and damage the enterocytes expressing MIC-A. A trial of a gluten-free diet is the most logical therapeutic option. Patients usually become symptom-free, and normal histologic features of the mucosa are restored. Some patients develop dermatitis herpetiformis, and a few enteropathy-associated T-cell lymphomas. Anticentromeric antibody is most specific for limited scleroderma (CREST syndrome) with esophageal dysmotility. The anti–DNA topoisomerase I antibody is most specific for diffuse scleroderma, in which gastrointestinal tract involvement by submucosal fibrosis may be more extensive, and malabsorption may be present. Antimitochondrial antibody is more specific for primary biliary cirrhosis. Antinuclear antibody is present in a wide variety of autoimmune diseases, but it is not characteristic of celiac sprue.
A potluck lunch party is held at the office at noon on Thursday. Various meats, salads, breads, and desserts that were brought in earlier that morning are served. Everyone has a good time, and most of the food is consumed. By mid- afternoon, the single office restroom is being used by many employees who have an acute, explosive diarrhea accompanied by abdominal cramping. Which of the following infectious agents is most likely responsible for this turn of events?
□ (A) Escherichia coli □ (B) Staphylococcus aureus □ (C) Vibrio parahaemolyticus □ (D) Clostridium difficile □ (E) Salmonella enteritidis □ (F) Bacillus cereus
(B) The clinical features suggest food poisoning caused by the ingestion of a preformed enterotoxin. Staphylococcus aureus grows in food (milk products and fatty foods are favorites) and elaborates an enterotoxin that, when ingested, produces diarrhea within hours. Some strains of Escherichia coli can produce various diarrheal illnesses, but without a preformed toxin. Vibrio parahaemolyticus is found in shellfish. Clostridium difficile can produce a pseudomembranous colitis in patients treated with broad-spectrum antibiotics. Salmonella enteritidis is most often found in poultry products, but the diarrheal illnesses develop within 2 days. Bacillus cereus is better known for growing on reheated fried rice; it produces an exotoxin that causes acute nausea, vomiting, and abdominal cramping.
During summer “Black and White Days,” a week-long local community celebration of the dairy industry (Holstein cows are black and white), a 40-year-old man has episodic abdominal bloating, flatulence, and explosive diarrhea. On physical examination, there are no remarkable findings. Laboratory studies show no increase in stool fat and no occult blood, ova, or parasites in the stool. A routine stool culture yields no pathogens. During the rest of the year, the patient does not consume milkshakes or ice cream sodas and is not symptomatic. Which of the following conditions best accounts for these findings?
□ (A) Celiac disease □ (B) Autoimmune gastritis □ (C) Cholelithiasis □ (D) Disaccharidase deficiency □ (E) Cystic fibrosis
(D) Disaccharidase (lactase) deficiency is an uncommon congenital condition (or a rare acquired condition) in which the lactose in milk products is not broken down into glucose and galactose, resulting in an osmotic diarrhea and gas production from gut flora. Affected individuals do not always make the connection between diet and symptoms, or they do not consume enough milk products to become symptomatic. Celiac disease also is diet related and results from a sensitivity to gluten in some grains. An autoimmune gastritis is most likely to result in vitamin B12 malabsorption. Cholelithiasis can cause biliary tract obstruction with malabsorption of fats and right upper quadrant abdominal pain. Cystic fibrosis affects the pancreas and mainly produces fat malabsorption.
For the past year, a 20-year-old man has had increasingly voluminous, bulky, foul-smelling stools and a 10-kg weight loss. There is no history of hematemesis or melena. He has some bloating, but no abdominal pain. On physical examination, there are no palpable abdominal masses, and bowel sounds are present. Which of the following laboratory findings is most likely to be present on examination of his stool?
□ (A) Increased stool fat □ (B) Giardia lamblia cysts □ (C) Occult blood □ (D) Vibrio cholerae □ (E) Entamoeba histolytica trophozoites
(A) This patient is most likely to have fat malabsorption. Smelly, bulky stools containing increased amounts of fat (steatorrhea) are characteristic. Pancreatic or biliary tract diseases are important causes of fat malabsorption. Giardiasis produces mainly a watery diarrhea. Malabsorption with steatorrhea is unlikely to be associated with bleeding. Cholera results in a massive watery diarrhea. Amebiasis can produce a range of findings from a watery diarrhea to dysentery with mucus and blood in the stool.
A 68-year-old woman has had substernal pain after meals for many years. For the past year, she has had increased difficulty swallowing liquids and solids. On physical examination, there are no remarkable findings. Upper gastrointestinal endoscopy shows a lower esophageal mass that nearly occludes the lumen of the esophagus. A biopsy specimen of this mass is most likely to show which of the following neoplasms?
□ (A) Adenocarcinoma □ (B) Leiomyosarcoma □ (C) Squamous cell carcinoma □ (D) Non-Hodgkin lymphoma □ (E) Carcinoid tumor
(A) Adenocarcinomas of the esophagus are typically located in the lower esophagus, where Barrett esophagus develops at the site of long-standing gastroesophageal reflux disease. Barrett esophagus is associated with a greatly increased risk of developing adenocarcinoma. Leiomyosarcoma of the esophagus is rare and is unrelated to a history of “heartburn.” Squamous cell carcinomas of the esophagus are most often associated with a history of chronic alcoholism and smoking. Malignant lymphomas of the gastrointestinal tract do not commonly occur in the esophagus and are not related to reflux esophagitis. Carcinoid tumors occur in different parts of the gut, including the appendix, ileum, rectum, stomach, and colon.
After an uncomplicated pregnancy, a 23-year-old woman, G2, P1, gave birth at term to a boy of normal weight and length. The infant initially did well, but at 6 weeks, he began feeding poorly for 1 week, and his mother noticed that much of the milk he ingested was forcefully vomited within 1 hour. On physical examination, the infant is afebrile, and there are no external anomalies. The physician palpates a midabdominal mass. Bowel sounds are active. The medical history indicates that the mother and her first child had the same illness during infancy. Which of the following conditions is most likely to explain these findings?
□ (A) Pyloric stenosis □ (B) Tracheoesophageal fistula □ (C) Diaphragmatic hernia □ (D) Duodenal atresia □ (E) Annular pancreas
(A) The infant’s condition occurred several weeks after birth because of hypertrophy of pyloric smooth muscle. Pyloric stenosis manifests the genetic phenomenon of a “threshold of liability,” above which the disease is manifested—more genetic risks are present. The incidence in males is 1/200 and in females is 1/1000, reflecting the fact that more risks must be present in females for the disease to occur; the threshold of liability would be exceeded more easily for males born into a family with the trait. Tracheoesophageal fistula, diaphragmatic hernia, and duodenal atresia are serious conditions that are manifested at birth and are often associated with multiple anomalies. Pyloric stenosis is an isolated condition that typically occurs without other anomalies. Annular pancreas is a rare anomaly.
A 53-year-old woman has had nausea, vomiting, and mid epigastric pain for 5 months. On physical examination, there are no significant findings. An upper gastrointestinal radiographic series shows gastric outlet obstruction. Upper gastrointestinal endoscopy shows an ulcerated mass that is 2 × 4 cm at the pylorus. Which of the following neoplasms is most likely to be seen in a biopsy specimen of this mass?
□ (A) Non-Hodgkin lymphoma □ (B) Neuroendocrine carcinoma □ (C) Squamous cell carcinoma □ (D) Adenocarcinoma □ (E) Leiomyosarcoma
(D) The most likely cause of a large mass lesion in the stomach is a gastric carcinoma, and this lesion is an adenocarcinoma. Malignant lymphomas and leiomyosarcomas are less common and tend to form bulky masses in the fundus. Neuroendocrine carcinomas are rare. Squamous cell carcinomas appear in the esophagus.
A 60-year-old man has had increasing fatigue for the past 8 months. On physical examination, he appears pale. On digital rectal examination, no masses are palpable, but a stool sample is positive for occult blood. Physical examination of the abdomen shows active bowel sounds with no masses or areas of tenderness. Laboratory studies show hemoglobin, 8.3 g/dL; hematocrit, 24.6%; MCV, 73 μm3; platelet count, 226,000/mm3; and WBC count, 7640/mm3. Colonoscopy shows no identifiable source of the bleeding. Angiography shows a 1-cm focus of dilated and tortuous vascular channels in the mucosa and submucosa of the cecum. What is the most likely diagnosis?
□ (A) Mesenteric vein thrombosis □ (B) Internal hemorrhoids □ (C) Angiodysplasia of the colon □ (D) Collagenous colitis □ (E) Colonic diverticulosis
16 (C) Angiodysplasia refers to tortuous dilations of mucosal and submucosal vessels, seen most often in the cecum in patients older than 50 years. These lesions, although uncommon, account for 20% of significant lower intestinal bleeding. Bleeding usually is not massive, but can occur intermittently over months to years. This lesion is difficult to diagnose and is often found radiographically. The focus (or foci) of abnormal vessels can be excised. Mesenteric venous thrombosis is rare and may result in bowel infarction with severe abdominal pain. Hemorrhoids at the anorectal junction may account for bright red rectal bleeding, but they can be seen or palpated on rectal examination. Collagenous colitis is a rare cause of a watery diarrhea that is typically not bloody. Colonic diverticulosis can be associated with hemorrhage, but the outpouchings usually are seen on colonoscopy.
A 43-year-old woman has become increasingly tired and listless over the past 5 months. She has had menometrorrhagia for the past 3 months. On physical examination, there are no remarkable findings except for a positive result on stool guaiac testing. Laboratory studies show hemoglobin, 9.2 g/dL; hematocrit, 27.3%; and MCV, 75 μm3. Pelvic ultrasound reveals an enlarged uterus. A Pap smear shows abnormal cells of probable endometrial origin. Colonoscopy is performed, followed by partial colectomy; the gross appearance of the lesion is shown in the figure. Which of the following molecular abnormalities has most likely led to these findings?
□ (A) Mutation in a DNA mismatch-repair gene
□ (B) Germline inheritance of APC gene mutation
□ (C) Tyrosine kinase activation owing to c-KIT mutation
□ (D) Homozygous loss of PTEN gene
□ (E) Inactivation of the Rb protein by HPV-16
(A) The figure shows a large, fungating mass that is typical of adenocarcinoma of the right colon. Such cancers are unlikely to obstruct, but they can bleed a small amount over months to years, causing iron deficiency anemia. This relatively young woman has evidence for an additional cancer, an endometrial cancer, and this combination is most likely due to an inherited mutation in one of the DNA mismatch-repair genes, such as hMSH2 and hMLH1. Homozygous loss of these genes can give rise to right-sided colon cancer and endometrial cancer. Such a mutation is typically associated with microsatellite instability. In contrast the APC gene, a negative regulator of β-catenin in the WNT signaling pathway, is associated with familial adenomatous polyposis syndrome and most sporadic colon cancers. This latter pathway also is known as the “adenoma-carcinoma sequence” because the carcinomas develop through an identifiable series of molecular and morphologic steps. Mutation with activation of c-KIT tyrosine kinase activity occurs in gastrointestinal stromal tumors, which respond well to treatment with imatinib mesylate, a tyrosine kinase inhibitor also used to treat chronic myelogenous leukemia. Loss of the PTEN tumor-suppressor gene is seen in endometrial carcinomas not associated with colon carcinoma and with some hamartomatous polyps of the colon. Infection with some strains of human papillomavirus leads to Rb protein inactivation and development of cervical carcinoma.
A 30-year-old man has sudden onset of hematemesis after a weekend in which he consumed large amounts of alcohol. The bleeding stops, but he has another episode under similar circumstances 1 month later. Upper gastroesophageal endoscopy shows longitudinal tears at the esophagogastric junction. What is the most likely mechanism to cause his hematemesis? □ (A) Absent myenteric ganglia □ (B) Autoimmune inflammation □ (C) Herpes simplex virus infection □ (D) Portal hypertension □ (E) Vomiting □ (F) Widened diaphragmatic crura
(E) This man has Mallory-Weiss syndrome with esophageal tears from severe vomiting. Most cases occur in the context of alcohol abuse. The bleeding is usually not as life-threatening as varices. Absent myenteric ganglia occur with achalasia. Autoimmunity underlies scleroderma with fibrosis and esophageal obstruction. Herpes simplex virus infection causes ulcerations that are usually superficial and cause pain, but do not bleed significantly. Portal hypertension leads to dilation of esophageal submucosal veins, which can bleed profusely; in this case, the patient’s age argues against the presence of cirrhosis from alcohol abuse. Widened diaphragmatic crura are present with hiatal hernia that predisposes to gastroesophageal reflux, and this is not associated with alcohol abuse.
A 52-year-old man has had a 6-kg weight loss and nausea for the past 6 months. He has no vomiting or diarrhea. On physical examination, there are no remarkable findings. Upper gastrointestinal endoscopy shows a 6-cm area of irregular, pale fundic mucosa and loss of the rugal folds. A biopsy specimen shows a monomorphous infiltrate of lymphoid cells. Helicobacter pylori organisms are identified in mucus overlying adjacent mucosa. The patient receives antibiotic therapy for H. pylori, and the repeat biopsy specimen shows a resolution of the infiltrate. What is the most likely diagnosis?
□ (A) Chronic gastritis
□ (B) Diffuse large B-cell lymphoma
□ (C) Autoimmune gastritis
□ (D) Mucosa-associated lymphoid tissue tumor
□ (E) Crohn disease
□ (F) Gastrointestinal stromal tumor
(D) Certain gastrointestinal lymphomas that arise from mucosa-associated lymphoid tissue (MALT) are called MALT lymphomas. Gastric lymphomas that occur in association with Helicobacter pylori infection are composed of monoclonal B cells, whose growth and proliferation depend on cytokines derived from T cells that are sensitized to H. pylori antigens. Treatment with antibiotics eliminates H. pylori and the stimulus for B-cell growth. MALT lesions can occur anywhere in the gastrointestinal tract, although they are rare in the esophagus and appendix. In H. pylori chronic gastritis, which may precede lymphoma development, there are lymphoplasmacytic mucosal infiltrates. Diffuse large B-cell lymphomas and other non-Hodgkin lymphomas that are not MALT lymphomas do not regress with antibiotic therapy. Autoimmune gastritis is a risk for development of gastric adenocarcinoma. Crohn disease is rare in the stomach and is not related to H. pylori infection. Gastrointestinal stromal tumors are uncommon; these tumors may be proliferations of interstitial cells of Cajal, myenteric plexus cells that are thought to be the pacemaker of the gut.
A 70-year-old man takes large quantities of nonsteroidal anti-inflammatory drugs because of chronic degenerative arthritis of the hips and knees. Recently, he has had epigastric pain with nausea and vomiting and an episode of hematemesis. On physical examination, there are no remarkable findings. A gastric biopsy specimen is most likely to show which of the following lesions?
□ (A) Epithelial dysplasia □ (B) Hyperplastic polyp □ (C) Acute gastritis □ (D) Adenocarcinoma □ (E) Helicobacter pylori infection
(C) Prolonged use of nonsteroidal anti-inflammatory drugs is an important cause of acute gastritis. Excessive alcohol consumption and smoking also are possible causes. Acute gastritis tends to be diffuse and, when severe, can lead to significant hemorrhage that is difficult to control. Epithelial dysplasia may occur at the site of chronic gastritis. It is a forerunner of gastric cancer. Hyperplastic polyps of the stomach do not result from acute gastritis, but may arise in association with chronic gastritis. Acute gastritis does not increase the risk of gastric adenocarcinoma. Infection with Helicobacter pylori is not associated with acute gastritis.
A 44-year-old woman has had increasing difficulty swallowing liquids and solids for the past 6 months. On physical examination, her fingers have reduced mobility because of taut, nondeforming skin. A barium swallow shows marked dilation of the esophagus with “beaking” in the distal portion, where there is marked luminal narrowing. A biopsy specimen from the lower esophagus shows prominent submucosal fibrosis with little inflammation. Which of the following is most likely to produce these findings?
□ (A) Portal hypertension □ (B) Iron deficiency □ (C) Barrett esophagus □ (D) CREST syndrome □ (E) Hiatal hernia
(D) Esophageal dysmotility is the “E” in CREST syndrome, the limited form of systemic sclerosis (scleroderma). Although the disease is autoimmune, little inflammation is seen by the time the patient seeks clinical attention. There is increased collagen deposition in submucosa and muscularis. Fibrosis may affect any part of the gastrointestinal tract, but the esophagus is the site most often involved. Portal hypertension gives rise to esophageal varices, not fibrosis. An upper esophageal web associated with iron deficiency anemia might produce difficulty in swallowing, but this condition is rare. For a diagnosis of Barrett esophagus, columnar metaplasia must be seen histologically, and there is often a history of gastroesophageal reflux disease. Hiatal hernia is frequently diagnosed in individuals with reflux esophagitis and can lead to inflammation, ulceration, and bleeding, but formation of a stricture is uncommon.
A 35-year-old man has had epigastric pain for more than 1 year. The pain tends to occur 2 to 3 hours after a meal and is relieved if he takes antacids or eats more food. He has noticed a 4-kg weight gain in the past year. He does not smoke and drinks 1 glass of Johannisberg Riesling daily. The result of a urea breath test is positive, and a gastric biopsy specimen contains urease. He begins a 2-week course of antibiotics, but on day 4, he feels better and discontinues treatment. Several weeks later, the epigastric pain recurs. If the patient does not seek further treatment, which of the following complications is he most likely to develop?
□ (A) Hematemesis □ (B) Fat malabsorption □ (C) Hepatic metastases □ (D) Carcinoid syndrome □ (E) Vitamin B12 deficiency
(A) The clinical symptoms in this case suggest peptic ulcer disease. In most cases, peptic ulcers are associated with Helicobacter pylori infection. These bacteria secrete urease, which can be detected by oral administration of 14C-labeled urea. After drinking the labeled urea solution, the patient blows into a tube. If H. pylori urease is present in the stomach, the urea is hydrolyzed, and labeled carbon dioxide is detected in the breath sample. In the biopsy urease test, antral biopsy specimens are placed in a gel containing urea and an indicator, and if H. pylori is present, the color changes within minutes. If not properly treated, peptic ulcers can produce many complications, including massive bleeding that can be fatal. The patient does not have fat malabsorption because fat absorption does not occur in the stomach. Peptic ulcers rarely progress to gastric carcinoma; metastases are unlikely. Carcinoid tumors can occur in the stomach, but they are rare and are not related to peptic ulcer disease, which this patient has. Vitamin B12 deficiency can occur with autoimmune atrophic gastritis because intrinsic factor, which is required for vitamin B12 absorption, is produced in gastric parietal cells
A 27-year-old man has sudden onset of marked abdominal pain. On physical examination, his abdomen is diffusely tender and distended, and bowel sounds are absent. He undergoes surgery, and a 27-cm segment of terminal ileum with a firm, erythematous serosal surface is removed. The microscopic appearance of a section through the excised ileum is shown in the figure. Which of the following additional complications is the patient most likely to develop as a result of this disease process?
□ (A) Metastatic adenocarcinoma □ (B) Mesenteric artery thrombosis □ (C) Intussusception □ (D) Hepatic abscess □ (E) Enterocutaneous fistula
(E) The ileum shows chronic inflammation with lymphoid aggregates. The inflammation is transmural, affecting the mucosa, submucosa, and muscularis. A deep fissure extending into the muscularis also is seen. These histologic features are highly suggestive of Crohn disease. Extension of fissures into the overlying skin can produce enterocutaneous fistulas, although enteroenteric fistulas between loops of bowel are more common. Although the risk of adenocarcinoma is increased in Crohn disease, this complication is less common than sequelae of inflammation. Mesenteric artery thrombosis, typically a complication of atherosclerosis, is unlikely in a 27-year-old man. Intussusception may occur when there is a congenital or acquired obstruction in the bowel. Hepatic abscess can follow amebic colitis.
An 8-month-old, previously healthy infant girl develops a watery diarrhea that lasts for 1 week. The infant has a mild fever during the illness, but has no abdominal pain or swelling. On physical examination, her temperature is 37.7°C. A stool sample is negative for occult blood, ova, or parasites. Her parents are told to give her plenty of fluids, and she recovers fully. Which of the following organisms is most likely to produce these findings?
□ (A) Campylobacter jejuni □ (B) Cryptosporidium parvum □ (C) Escherichia coli □ (D) Listeria monocytogenes □ (E) Norwalk virus □ (F) Rotavirus □ (G) Shigella flexneri □ (H) Vibrio cholerae
(F) Rotavirus is the most common cause of viral gastroenteritis in children. It is a self-limited disease that affects mostly infants and young children, who can lose a significant amount of fluid relative to their size and can quickly become dehydrated. The death rate is less than 1%. Campylobacter jejuni is more often seen in children and adults as a foodborne cause of fever, abdominal pain, and diarrhea. Cryptosporidiosis most often causes a watery diarrhea in immunocompromised adults. Enterohemorrhagic strains of Escherichia coli can produce hemolytic-uremic syndrome in young children. Listeriosis can be a congenital infection that is present along with meningitis and sepsis at birth; in infants, children, and adults, it is a food-borne or water-borne infection that tends to occur in epidemics. Norwalk virus is a common cause of diarrheal illness in adults. Shigellosis produces dysentery with bloody diarrhea. Cholera results in massive loss of fluid.
